.container{
  border: 1px solid red;
  padding: 0 150px;
  min-width: 450px;
  overflow: hidden; /*为了撑起元素，作用同下*/
}
/*为了撑起容器，作用同overflow: hidden;*/
/*.container:after{
  content: "";
  display: block;
  clear: both;
}*/

.box{
  min-height: 200px;
  float: left;
}

.main{
  background-color: #e11;
  width: 100%;
}

.left{
  background-color: #3f3;
  width: 150px;
  margin-left: -100%;
  position: relative;
  left: -150px;
}

.right{
  background-color: #ff5;
  width: 150px;
  margin-left: -150px;
  position: relative;
  right: -150px;
}
